Method and means for the formation of breathing tubes and the like



Nov. 23, 1937. K. CONNELL 2,099,843

METHOD AND MEANS FOR THE FORMATION OF BREATHING TUBES'AND THE LIKE Original Filed Oct. 5, 1935 Patented Nov. 23, 1937 UNITED STATES PATENT OFFICE METHOD AND MEANS FOR THE FORMA- TION F BREATHING TUBES AND THE LIKE Karl Connell, Branch, N. Y.

Claims.

This invention relates to methods and means for the formation of flexible tubing, such for instance as tubes adapted for use as breathing tubes and the like.

This application is a division of my co-pending application, Serial No. 43,650, filed October 5, 1935.

Among the objects of the invention are the provision of improved methods and means whereby the formation of breathing tubes and the like may be facilitated.

A more specific object of the invention is the provision of a particularly effective and efiicient method for the formation of helically or similarly grooved breathing tubes and the like.

A still more specific object is the provision of an improved method. of removing such a tube from its mandril.

Another more specific object is the provision of simple and effective apparatus adapted for use in the formation of corrugated. breathing tubes and the like.

A further object is the provision of apparatus whereby the removal of the tube from the mandril is facilitated.

Other objects of the invention will in part be obvious and will in part appear hereinafter.

The invention accordingly comprises the several steps and the relation and order of one or more of such steps with respect to each of the others, and the apparatus embodying features of construction, combinations of elements and arrangement of parts which are adapted to effect such steps, all as exemplified in the following detailed disclosure, and the scope of the application of which will be indicated in the claims.

For a fuller understanding of the nature and objects of the invention reference should be had to the following detailed description taken in connection with the accompanying drawing, in which:

Figure l is a side view of a breathing tube such as may be formed by the use of the invention, a portion of the front wall being cut away to show the interior of the tube; and

Fig. 2 is a somewhat diagrammatic, partly sectional View exemplifying a form of apparatus embodying the invention and exemplifying the procedure at the stage wherein the tube is released from the mandril.

By far the simplest method of forming helically grooved and similar types of tubing is to mold the same upon a mandril which conforms in shape to the interior of the tube desired. Thereupon the tubing must be removed from the irregular surface of the mandril. Annularly corrugated tubes can be removed from the forming mandril with comparative ease by expanding the tube pneumatically, but the utmost difliculty has been experienced in removing tubes having continuous spiral interior grooves because the tube tends to expand partially over its entire length and permits the escape of the expanding gas at the free end of the tube. If this end is closed in the ordinary manner the mandril cannot be removed. It is to the provision of method and means adapted to overcome these difiiculties that the present invention is primarily directed.

In accordance with the invention considered from a method standpoint an expansible tube may be molded upon a helical mandril or the like, having a closed expansion chamber including a container of sufficient capacity to receive the mandril provided, the end of the container being inserted between the tube and the mandril at one end thereof, and fluid pressure suflicient to expand the tube beyond the. mandril applied. The mandril is then removed into the closed chamber and the fluid pressure released to collapse the tube.

In accordance with the invention considered from an apparatus standpoint there may be provided a suitable mandril, a container of sufficient size to receive the mandril and having an end adapted to be inserted between one end of the mandril and of an expansible tube formed thereon, said container providing a substantial closure at said end, means to provide a substantial closure at the other end of the mandril and the tube, and means to deliver fluid pressure between the tube and the mandril.

In Fig. 1 there is exemplified one type of tube 4 adapted to be formed by means of the invention. As exemplified, this tube is of the general character disclosed and claimed in my co-pending application, Serial No. 43,650, and is in the form of a flexible non-collapsing breathing tube formed of soft rubber and helical in contour, to provide a continuous exterior helical groove 6, a central passageway 1, and a continuous interior helical groove 8. The tube is formed at its respective ends with an integral bulb or fitting H, and with an integral tubular portion l2.

Tubes of this general character may be readily molded upon a helically-threaded mandril, but it has hitherto been a matter of extreme difiiculty to disengage the tube from the mandril, in accordance with any of the ordinary tube-forming procedures. The same problems arise in the removal of tubing from any mandril having protruding portions which extend the length of the mandril as well as laterally thereof. Pursuant to the present invention, when the molding operation is completed, one end of a closed container of suilicient size to receive the mandril is inserted between the tube and the mandril at one end thereof, the other end thereof is closed, and fluid pressure (for instance, gaseous pressure, as compressed air)' applied between the tube and the mandril, for instance by a connection at said other end, to expand the tube,--the container serving to prevent escape of the said fluid until the tube is sufiiciently expanded to clear the proiii to provide the tube 4.

truding rib on the mandril,whereupon the mandril may be dropped or pressed into the eontainer and the gaseous pressure released to ,col-

lapse the tube.

being expanded manually, or by suitable mechanical means, so as to slip over the end of the container. Thereupon a sleeve 32 is slipped between the other end of the tube and the mandril. The

sleeve 32 is connected by a conduit 33 to a supply of gaseous pressure, such as compressed air, as indicated at 34;. thus serving to close said other end of the tube. Upon the opening ofa valve 35 the gaseous pressure expands the tube to the position indicated in Fig. 2, the container 3| serving to prevent the escape of such pressure as has readily passed along the convolutions of the interior groove 8. Since a closure is provided at both ends of the tube the increased pressure will necessarily expand the tube- It is'to be understood in this connection that such closure as'is contemplated is merelyan efiective closure, and

that'pressure from a line may be utilized as well as pressure from a tank. When the tube is sufli- .ciently expanded, the'mandril may be dropped or pressed into the container. As will be apparent the container is of suflicient size to receive the mandril, as in the position indicated in dotted lines in Fig. 2.. As will be apparent it is important that the entire space which is subjected to fluid pressure be substantially closed. On the other hand, the pressure may be introduced at any suitable point other than that shown. For instance, it may be introduced thru the container 3|, the end of the sleeve 32 in this case being closed to provide a cup-like closure.

' During the expanding operation, excessive expansion of the tube is prevented by a jacket which may .be formed of canvas, metal or other suitable material, as indicated at 36. After the removal of the mandril, the valve 35 may be closed and the pressure released to collapse the .tube. The

importance of provision of means to prevent undue distensionof the weaker portionsof the tube will be appreciated when it is understood that tubes suitable for gas masks and mine rescue work are desirably formed of rubber of tire tread quality of 60 durometer and of a thickness in excess of .125", and may require 60 pounds expanding force. Since the tubes additionally to expansion in diameter often elongate under pressure approximately 80% in addition to their normal length in the process of stripping, the jacket should be of suflicient length to take care of this 7 expansion.

Since certain changes in carrying out the above 7 method and in the constructions set forth, which embody the invention, may be made without departing from its scope, it is intended that all matter contained in the above description or shown in the accompanying drawing shall be interpreted as illustrative and not in a limiting sense.

I claim:

1. The method of forming breathing tubes and the like which comprises molding and curing an expansible tube on a mandril, providing an expansion chamber including a container of suflicient capacity to receive the mandril, the end of said container being inserted between the tube expansible tube on a mandril, inserting between the tube and the mandril at one end thereof a closed container of sufiicient capacity to receive the mandril, providing a closure at the other end, applying gaseous pressure between the tube and the mandril to expand the tube beyond said pro-' truding portions, removing the mandril into said container, and releasing the gaseous pressure to collapse the tube.

3. Apparatus 'for the formation of breathing tubes and the like comprising a mandril, a container for the mandril of suflicient size to receive the mandril and having an end adapted to be inserted between one end of the mandril and of an expansible tube formed thereon to provide a closure at said end, means to provide a substantial closure at the other end of the mandril and tube, and means to deliver fluid pressure between said tube and said mandril.

4. Apparatus for the formation of breathing tubes and the like comprising a mandril, a container for the, mandril of sufficient size to receive the mandril and having an end adapted to be inserted between one end of the mandril and of an expansible tube formed thereon to provide a closure at said end, means to provide a substantial closure at the other end of the mandril and tube, means to deliver fluid pressure between said tube and said mandril, and a jacket about said mandril'to prevent undue expansion of said tube, said jacket having a length greater than the mandril.

'5.'The combination with a threaded mandril and a helical expansible tube thereon, of means providing closures at both ends of the tube, the

closure at one end providing a chamber of win cient size to receive the mandril, and means to inflate said tube-to free it from the mandril and to permit the mandril to be received by 'said' chamber. I

' KARL CONNELL. 

